1. Field of the Invention
The present invention relates to the field of power management in computer systems, and in particular, to the field of detecting bus utilization in a computer system.
2. Description of Related Art
Many computer systems which include at least one automated power management capability rely on an idle timer to determine when power management measures should be taken. The idle timer is loaded with an initial idle time, starts counting down from that time and then, if a system activity event is detected, the idle timer is reloaded with the initial idle time. If the idle timer expires before a system activity event is detected, the system is considered idle and may enter a suspend mode or other power management measures may be taken. The system activity events which cause the idle timer to reload or reset are primarily input/output (I/O) addresses and interrupts such as keyboard or mouse events.
An issue arises, however where the computer system is engaged in a processing activity which is not detected by the detection circuitry coupled to the idle timer and thus, which does not cause the idle timer to reset. In such a case, the computer system may enter a suspend mode even while processing is underway. For example, because the playing of multimedia movies on a computer system may not cause any I/O address or interrupt events, the activity may go undetected by the computer system and the computer system may be considered idle. In this case, the computer system may enter a suspend mode while the movie is still in progress.
Thus, a method and apparatus for detecting activity which does not necessarily generate I/O addresses and interrupts is needed.